spark plugs DATSUN 210 1979 User Guide

Page 187 of 548


INSPECTION

I

Disconnect

high
tension

cables

from

spark
plugs
by
pulling
on

boot

not
on
cable
itself

2

Remove

spark

plugs

3

Check
electrodes
and
inner

and

outer

porcelains
of

plugs
noting
the

type
of

deposits
and
the

degree
of

electrode
erosion

Refer
to

Fig
EE

76

Normal
Brown

to

grayish
Ian
de

posits
and

slighl
electrode
wear

indicate
correct

spark

plug
heat

range

Carbon
fouled

Dry
fluffy
carbon
de

posits
on
the
insulator
and
elec

trode
are

mostly
caused

by
slow

speed
driving
in

city
weak

ignition

too
rich
fuel
mixture

dirty
air

cleaner
etc

H
is
advisable
to

replace
with

plugs

having
hotter
heat

range

Oil
fouled

Wet
black

deposits
show

excessive

oil
entrance
into

comb
us

tion
chamber

through
worn

rings

and

pistons
or
excessive

clearance

between
valve

guides
and
stems
If

the
same
condition
remains
after

repair
use
a
hotter

plug

Overheating
White
or

light
gray
insu

lator
with
black
or

gray
brown

spots
and
bluish
burnt
electrodes

indicate

engine
overheating
More

over
the

appearance
results
from

incorrect

ignition
timing
loose

spark
plugs
low
fuel

pump
pres

sure

wrong
selection
of
fuel

a

hotter

range
plug
etc

H
is
advisable
to

replace
with

plugs

having
colder
heat

range

4
After

cleaning
dress
electrodes

with
a
smaU
fme
file
to
flatten
the

surfaces
of
both

center
and
side
elec

trodes
in

parallel
Set

spark
plug

gap
to

specification

5

Install

spark

plugs
and

torque

each

plug

6
Connect

spark
plug
wires

CLEANING

AND

REGAP

Clean

spark
plugs
in
a
sand
blast
Engine
Electrical

System

SPARK

PLUG

Conventional

type

Normal

Overheating

Multi

gap
type

Nonnal

Overheating

type
cleaner
Avoid
excessive

blasting

Clean
and
remove
carbon
or
oxide

deposits
but
do
not
wear

away
porce

lain
If

deposits
are
too
stubborn

discard

plugs

After

cleaning
spark

plugs
renew

firing
surface
of
electrodes
with
file

mentioned

above
Then
check

spark

plug
gap
with
wire

feeler

gauge
All

spark
plugs
new
or
used

should
have

the

gap
checked
and
reset

by
bending

ground
electrode

EEOSO

Fig
EE
77
Setting
Spark
Plug
Gap

Except
FU
model

EE
29
Carbon

fouled

EE079

Worn

Carbon

fouled

Worn

EE601

Fig
EE

76

Spark

Plug

EE586

Fig
EE
78

Setting
Spark
Plug

Gap
FU
models

Page 195 of 548


Engine
Electrical

System

IV
IGNITION
CIRCUIT

When

engine
does
not

start

If

there
is
no

problem
in
fuel

system

ignition
system
should
be

checked
This
can
be

easily
done

by

detaching
a

high
tension
cable
from

distributor

starting
engine
and
ob

serving
oondition
of

spark
that

occurs
between

high
tension
cable
and

engine

block
After

checking
this

repair
as

necessary
tery
and
anti
dieseliilg
wlenoid

valve
connector
to
cuI
off

supply

of
fuel
10

engine
Then
observe
the

condition
of

sparks
while
starter

motor
is
in

operation

Note
Turn

ignilion
switch
off
and

disconnect
ground
cable
from
bat

Condition
Location

Probable
cause
Corrective
action

No

spark
at
all
Distributor

Breakage
of
lead
wire
on
low
tension

side

Repair

Poor
insulation
of

cap
and
rotor
head

Replace

Open
pick
up
coil

Replace

Air

gap
wider
than

specification
Adjust

Ignition
coil
Wire

breakage
or
short
circuit

of
coil

Replace
with
new
one

High
tension
cable
Wire

coming
off

Repair

Faulty
insulation

Replace

IC

ignition
unit

Faulty
IC

ignition
unit

Replace

Breakage
of
circuit

Replace

Detached
connection

Repair

Spark
length
Spark
plugs
Spark
plug

gap
too

wide
Correct
or

replace

More
than
6

mm

Too

much
carbon
Clean
or

replace

0
24
in

Broken
neck

of
insulator
Replace

Expiration
of

plug
life

Replace

Distributor
Air

gap
too
wide

Correct

IC

ignition
unit

Faulty
IC

ignition
unit

Replace

Breakage
of
circuit

Replace

Detached
connection

Repair

EE
37

Page 196 of 548


2

Engine
rotates
but
does
not

run

smoothly

This

may
be
caused

by
the

ignition

Condition

Location

Engine
misses

Distributor

Ignition
coil

High
tension

cable

Spark
plugs

IC

ignition
unit

Engine
causes

knocking

very

often
Distributor

Spark

plugs

Engine
does

not

deliver

enough

power
Distributor

Spark
plugs
Engine
Electrical

System

system
or
other

engine
conditions
not

related

to

ignition
system
Therefore
first

complete

inspection
of

ignition

system
should
be
carried
out

Probable
cause

Foreign
matter

onpicl
up
coil

Improper
air

gap

Leak
of

electricity
at

cap
and
rotor
head

Breakage
of

pick
up
coil
lead
wire

Worn
or

shaky
breaker

plate

Worn

or

shaky
distributor

driVing
shaft

Layer
short
circuit

or
inferior

quality

coil

Deterioration
of
insulation
with

cense

quenlleak
of

electricity

Fouled

Leak
of

electricity
at

upper
porcelain

insulator

Spark
plug
gap
too
narrow

Faulty
IC

ignition
unit

Breakage
of

circuit

Detached
connection

Improper

ignition
timing
too
advanced

Coming
off
or

breakage
of

governor

spring

Worn

pin
or
hole
of

governor

Burnt
too
much

Improper
ignition
timing
too

retarded

Improper
functioning
governor

Foreign
particles
stuck
in
air

gap

Fouled

EE
38
Corrective
action

Clean

Correct

Repair
or

replace

Replace

Replace
assembly

Replace
aSsembly

Replace
with

good
one

Replace

Clean

Repair
or

replace

Correct
or

replace

Replace

Replace

Repair

Correct

Correct
or

replace

Replace

Replace

Correct

Replace
assembly

Clean

Clean

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